(a) Field of the Invention
The present invention relates to a power bank apparatus, and more particularly to a power bank apparatus capable of adjusting an output voltage automatically or manually to supply electric power to different electronic devices, so as to reduce the number of various adapters.
(b) Description of the Prior Art
As digital electronic products have become an indispensable part of our life, we often use digital electronic products such as digital cameras, digital photography equipments, and even MP4 digital audio/video players regardless of our requirements at home, in office, or on a tour or a business trip. For instance, users usually use digital cameras and MP4 players for fun and personal digital assistants or notebook computers for business, and thus the digital electronic products bring tremendous convenience to users.
As to those portable digital electronic products with no utility power supply, the power supply time of the battery becomes a big issue, and the battery manufactured by original manufacturers is too expensive and the power supply time is too short, and some of the batteries cannot be recharged during the use of the digital electronic product. Obviously, such digital electronic products cannot maximize their utility, and thus power bank is introduced to overcome this issue.
With reference to FIG. 1 for a structure of a general power bank 1, the power bank 1 includes a plurality of built-in chargeable batteries 11 and a transmission line 12 for connecting the power bank 1 with an electronic device 2 to supply electric power to the electronic device 2. To meet the voltage requirement for different digital electronic products, users need to buy many different power adapters for different output voltages, and thus causing inconvenience to users.